A major goal of this study is to develop a better understanding of the biochemical events that initiate the blood coagulation process and fibrinolysis. These reactions lead to the formation of the fibrin clot and its degradation. These investigations will focus on the interaction of prekallikrein, factor XII and factor XI and their mechanism of activation. Another goal of this project is to study in greater detail the mechanism by which factor VIII and factor V are activated and degraded during the coagulation process. A third focus of this research project is to examine the biosynthetic pathway for several of the coagulation factors in a cell free system. These studies involve the isolation and characterization of the messenger RNAs for prothrombin, the alpha, beta, and gamma chains of fibrinogen and for plasminogen.